Superplasticity of Al-Mg and Al-Zn-Mg-Cu alloys with scandium addition

Superplasticity is a property of metallic materials which, at special working condition, enables to achieve very high elongations without local necking during tensile test. Sheets of aluminium superplastic alloys are used for making very complicated items with only one working operation what reduces manufacturing and material costs considerably. The use of superplastic alloys is suitable for making components of cars and other vechiles, components of aeroplanes and space vehieles, components of apparatuses like housings, lining of billings, decorative items etc. The intention of proposed research project is making the Al-Mg, Al-Mg-Mn and Al-Zn-Mg-Cu alloys with superplastic properties. Foreseen 12 alloys will be made with and without scandium addition in the interval from 0,2 to 0,5 mass %. The alloys will be thermomechanicaly treated with various combinations of annealings and deformations. Superplastic properties of alloys with various scandium additions and after various thermomechanical treatments will be examined and investigated with tensile test at elevated temperatures. The variable parameters will be the working temperatures and strain rates. Superplastic properties of tested alloys will be determined on the base of maximal achieved elongations, flow stresses and values of strain rate sensitivity exponents. Microstructures of alloys depending on chemical composition and thermomechanical treatments will be determined with classical and modern metalographic methods.